It is still somewhat surprising that Duffy was given the call for the start, as he is in his age-22 season and has all of 36 innings at Triple-A (and just 39 2/3 at Double-A). The Royals like what they have seen in that short stretch, though, and have called him up to see what he can do. It's hard to argue with the 10.8 strikeouts per nine and the K/BB ratio of 4.3 at Omaha, both of which aren't too far off of his career rates.

Duffy was selected in the third round of the 2007 draft out of what Baseball Prospectus 2008 called an "obscure California high school," and immediately pitched like someone selected earlier in the draft. Duffy struck out 63 hitters in 37 1/3 innings at the Rookie level, posting an ERA of 1.45 and a K/BB of 3.7 despite allowing 4.1 walks per nine.

Duffy never showed that lack of control again, as the highest walk rate he has posted since in a full year is 2.9 per nine, but the strikeouts remained. The left-hander struck out 11.2 per nine in his first taste of Single-A, and while he slid back a bit when he played for High-A Wilmington in 2009, it's hard to argue with 125 punchouts in 126 innings (against just 41 walks) and the 2.98 ERA—his loftiest as a pro.

The 2010 season is when things turned odd. In the spring, Duffy retired, taking a leave from baseball to figure out what it was he wanted to do. This was strange for a number of reasons—for one, he was all of 21 years old, and second, it's not like he was a highly touted prospect wondering where all of the talent and production he had back in high school went. Given his third-rounder status and his performance, it was exactly the opposite situation for him.

Regardless, he needed the mental break, and it didn't hurt him at all when he returned. He pitched for four teams at three levels, making four starts for two Rookie clubs, returning to High-A where he had spent his 2009 campaign for a spell, then finishing up the year in Double-A. Duffy struck out 9.3 per nine and walked just nine batters in his 39 2/3 innings there.

For his efforts, Duffy was named the #67 prospect in the minors on Goldstein's Top 101 list. He was the seventh-best prospect in the Royals system, a four-star pitcher with a mid-90s fastball, a changeup he can rely on, and a breaking ball that works just fine as a third pitch.

As mentioned above, he has outperformed even those expectations at his short time at Triple-A, and now finds himself in the majors on a Royals team that was .500 heading into Tuesday night's action, with the distinct possibility that he could be their top starter by year's end.

That may seem like a bold statement to make, given his lack of experience in the upper minors and a resume bereft of any major league innings, but have you seen the rotation in Kansas City lately? Luke Hochevar is the #1 starter, they currently depend on Jeff Francis to both be there and pitch well, and the next guys in line are Kyle Davies and Sean O'Sullivan, two pitchers who wouldn't even make it as fifth starters on most contending clubs. Bruce Chen is currently on the DL, and Vin Mazzaro, tonight's original scheduled starter, was forced to pitch after Davies was hurt on Monday: Mazzaro, who entered Monday's contest with a 4.50 ERA, now needs to throw 26 scoreless innings in a row to get back to that figure after allowing 14 earned runs in his relief appearance. Duffy could disappoint and still come out ahead of the game when he is being compared to that crew.

That said, there are some warning signs here that we at least need to be aware of before we empty our FAAB coffers at Duffy's feet. He has thrown over 100 innings in a season exactly once, back in 2009. Following last season's retirement and return, Duffy made just 14 starts and logged 62 1/3 frames. Unless the Royals are overly careful with his young arm, he will set a career high for innings, and will do so with most of those coming against the most talented hitters in the world (except for when he faces the rest of the AL Central, I mean).

PECOTA projected Duffy for a 4.32 ERA, 1.45 WHIP, 8.4 strikeouts per nine, and a K/BB over two. That assumes Kansas City's defense fails him—he has a projected BABIP of .312—and also that his control abandons him. Remember the walk rate over four that he hasn't seen since? PECOTA projects him for 4.1 walks per nine.

Except for in regards to strikeouts, that isn't a sexy line for fantasy purposes. PECOTA does like Duffy at the 70th percentile and up, though, to the point where he would merit being rostered, and that projection came out before Duffy dominated Triple-A. His projected ERA ranges from 4.07 at the 70th to 3.67 at the 90th percentile, with more manageable WHIPs of 1.34 and 1.19. Those are intriguing lines, and the possibility of seeing them is absolutely worth the FAAB dollars or waiver priority you will use up to acquire Duffy.

Don't be surprised if Duffy doesn't mow down MLB hitters like he has in the minors, but by the same token, this is a pitcher who retired and came back even better than he was, a pitcher who has had no issues at either level of the high minors (albeit in small samples). Would you be surprised if he made the Rangers look silly tonight? Given the performances of John Lamb and Mike Montgomery, Duffy may be the lone Royals farmhand on the mound who makes an impact in 2011. He is owned in just 13 percent of CBS leagues as I write this, a seven percent jump from last week, so snag him while you can if you have a need for pitching depth or are in a keeper format.